Improving High‐Temperature Operational Stability of Inverted Perovskite Solar Cells Through MXene Heat‐Dissipating Layers

ABSTRACT Despite inverted perovskite solar cells (iPSCs) having reached power conversion efficiencies (PCEs) of about 27% with long‐term stability at room temperature, their commercial devices must prevent heat‐induced performance degradation. In PSCs, 2D MXenes have been employed to enhance their long‐term stability at high temperatures; however, a deep understanding of the heat management mechanism of applying MXenes at interfaces is still lacking. Herein, we investigate the application of MeO‐2PACz‐functionalized MXenes at the hole transport layer (HTL) interface in iPSCs using MeO‐2PACz as the HTL. PSCs reached PCEs of 23.02 ± 1.14%, observing a 400% enhancement in their operational stability, spanning the T 80 lifetime at 65°C from 141 to 687 h. HAADF‐STEM imaging and STEM‐EELS analysis confirmed the effective intercalation of the MeO‐2PACz within the MXene atomic nanolayers. Thermal conductivity measurements and simulations revealed that the application of the functionalized MXenes can effectively dissipate the heat from the perovskite absorber, reducing the perovskite temperature by about 20 ± 6%. Overall, the fourfold extension of T 80 by using MeO‐2PACz‐functionalized MXenes in iPSCs is attributed to the synergy between reduced thermal accumulation and improved buried‐interface quality, including defect passivation, enhanced charge extraction, and suppressed ion migration.